Without DNA evidence they might never have been caught. So the convictions
last week of two savage killers might seem a powerful argument that Britain
should have a compulsory DNA database covering every person in the country.
The first strand in this gruesome double-helix involved Steve Wright, a quiet
man who led a deadly secret life. In 2003 Wright was convicted of stealing a
small sum of money while working as a hotel barman. His profile was
routinely added to the national DNA database.
Three years later, young prostitutes working in Ipswich began disappearing. On
December 2, 2006, the body of Gemma Adams, 25, was found in a stream; six
days later, the body of Tania Nicol, 19, was discovered, also in water. They
had been stripped, asphyxiated and dumped. A serial killer was on the loose.
Two days after that, Anneli Alderton, 24, was found in woodland, her body laid
out like a crucifix. This time police were able to recover significant
samples from the corpse, which were sent for analysis.
By December 17, forensic scientists had extracted a DNA profile. Less than an
hour later the national database, which is in Milton Keynes, found a match,
giving Suffolk police Wright’s name.
Last week Wright – whom locals had thought was an unassuming golf obsessive –
was convicted of five murders and sentenced to life in prison. If he had not
been identified by DNA, he might have killed even more. He had been
questioned by police twice in the course of their investigations, but had
not aroused suspicion.
The second case centred on Mark Dixie, a pub chef from Surrey. Dixie was
regarded by friends as an ordinary guy who enjoyed a party. He had managed
to keep hidden a history of violent sexual assaults and had emigrated to
Australia in 1993 before the collection of DNA became routine. He was not on
the national database when he returned to Britain.
In September 2005 Dixie was prowling the streets in the early hours when he
chanced upon Sally Anne Bowman, an 18-year-old aspiring model, returning
home. He pounced in the driveway of her house and stabbed her repeatedly,
inflicting wounds that one detective said were “off the scale”. Dixie
sexually defiled Bowman’s corpse.
Although police recovered DNA samples of the attacker, the database held no
match. For nine months the murder investigation made little progress. The
police, believing the killer lived locally, had a list of more than 22,000
suspects.
Then in June 2006, Dixie was arrested after a fight broke out among football
fans watching an England match in a pub.
The police were puzzled as to why he burst into tears as he was taken away.
Dixie knew what was coming. His DNA was taken and within days was matched to
the Bowman murder case. Dixie was last week sentenced to life.
The savagery of his crime spurred police to speak out. Detective
Superintendent Stu-art Cundy, who led the investigation, said: “I am all for
a DNA register [of everybody], set up with the appropriate safeguards. If we
had one, we could have identified Sally Anne’s murderer in 24 hours, which
means we could have protected everyone else out there.”
The use of DNA may seem like a “magic bullet” that can clear up cases quickly
and bring resolution to unsolved crimes.
Today we report that Scot-land Yard believes new forensic evidence, including
DNA samples, will enable the five original suspects to be tried again for
the racist murder of Stephen Lawrence in 1993. New DNA analysis has also led
to charges being brought against Robert Napper, 41, for the murder of Rachel
Nickell on Wimbledon common, south London, in 1992.
But forensic experts and lawyers fear the use of DNA is already being pushed
to the limits. “We are riding for a fall,” said one.
Is there a case for a compulsory register of everybody’s DNA? Would the
benefits in solving crimes outweigh the invasion of privacy? Or are police
in danger of relying too much on DNA evidence that may not be as conclusive
as it seems? AT any time, several undetected homicidal psychopaths are
living freely in a country the size of Britain, according to psychologists.
“There will be a handful of serial killers at large right now,” said Keith
Ashcroft, a consultant forensic psychologist. “A small proportion of the
unexplained disappearances and unsolved murders will be down to serial
killers who have not been identified.”
They are often difficult to detect. Many appear normal, with their violence
secretly rooted in childhood problems. There may be no other element of
criminality, so no reason for such psychopaths to be on the national
database.
At present, it contains DNA profiles of 4.5m people, mostly those who have run
into trouble with the law. It is one of the largest DNA databases in the
world but still covers less than 10% of the population.
The police may now take and record the DNA of anyone who is arrested for a
recordable offence – whether they are subsequently found guilty or set free
without charge. About 80% of profiles on the database are male, 19% female
and 1% “unknown”. Thousands of children and about 40% of black men are on
it.
Every month about 3,500 matches are made between crime scene samples and DNA
profiles. In 2005 the database was used in 422 murder and manslaughter
trials, 645 rapes and 9,000 burglaries.
Supporters claim “if you have nothing to hide, you have nothing to fear” from
the system. Critics say the database is discriminatory and can put the
innocent at risk, especially since technical advances mean DNA can be
recovered from the tiniest samples.
The standard test for determining a DNA profile is called SGM Plus and is
regarded as highly reliable. It compares 10 sites on a piece of DNA, whereas
an earlier form of the test relied on only six matches.
The likelihood of two unrelated individuals showing the same full DNA profile
under the SGM Plus test is said to be one in a billion. Under the older
test, it was one in 50m.
It is not always that straightforward, however, because many samples provide
only a partial profile or match. The Home Office has admitted to The Sunday
Times that in more than 50,000 instances since 2001, DNA samples from crime
scenes have resulted in multiple matches on the national database.
In other words, partial profiles pointed the finger at more than one suspect,
sometimes many more. The police then have to rely on other evidence and,
provided that is the case, lawyers generally approve.
Mark George, a barrister who wrote a paper on DNA last month, said: “On
ordinary DNA testing, as far as I am aware, people are happy. [But] low-copy
number DNA is a whole different ball game. It’s controversial even within
the scientific community.” Low-copy number, or LCN, DNA is a technique that
creates a profile from tiny samples by replicating the DNA more times than
normal.
“In the conventional system, you need maybe 200 cells or 100 at a push to give
you the profile,” said Duncan Woods, a forensic scientist at Keith Borer
Consultants. “In theory, LCN can do it with just one cell, although in
reality you will probably need five or six.”
It is a system that has not been validated by scientific peer review, although
a report is due soon. It was LCN analysis that led Portuguese detectives to
believe Madeleine McCann had been in a hire car that was rented by her
parents after her disappearance.
In many countries, including the US, LCN evidence is not admissible in court.
Yet in Britain it is.
Orlando Pownall, a leading QC, also has his concerns. He pointed out that in
the Omagh bomb trial last December, LCN evidence produced a partial match
with a schoolboy from Nottingham who happened to be on the database.
“He would have been about six at the time of the bombing,” said Pownall,
so he was discounted. “But imagine if he had been a Republican living near
Omagh – he’d have been in the dock.”
The case failed, the judge delivered a denunciation of LCN and its use was
suspended pending a review. A few weeks later, however, it was reinstated.
“I’ve no doubt it could be valuable, but it’s got to be validated,” said
Pownall. “We are riding for a fall.”
One of the key problems, particularly with LCN evidence, is second-party
transmission: tiny samples of your DNA, for example, can easily be deposited
at a crime scene by someone else with whom you have been in contact. As
Professor Allan Jamieson, an expert on DNA testing, explained: “I shake your
hand. I touch the steering wheel of my car. The car is later involved in a
crime – and they find your DNA. It’s a very real problem.” THE risk of the
innocent being accused is compounded by what might be called the “CSI
effect”, after the popular tele-vision drama series. Its main crime scene
investigator is fond of warning his colleagues: “Follow the evidence, it
never lies.”
Some investigators and juries are so convinced DNA evidence is infallible that
absurd situations can arise.
Last year detectives reinvestigating a case of rape got a DNA profile from a
strand of hair caught in a ring worn by the victim. The DNA identified Mark
Minick, who was charged with the rape.
Yet when the case arrived in court, it fell apart. Minick is white, small and
slim – while the victim had described her attacker as black, large and tall.
She is thought to have picked up Minick’s hair by chance from a blanket in
the hospital where he had worked.
Lawyers raise other concerns, too. It is possible for an innocent person’s DNA
to be planted at a crime scene, either to mislead police or to incriminate
an enemy of the real perpetrator.
Cost is another factor. The police are pouring resources into DNA and
forensics: at one point in the Wright case, 250 scientists were working on
the investigation. Yet defence lawyers complain they sometimes struggle to
get funding for their own tests – and that occasionally there is no crime
scene material left for them to check once prosecution tests have been done.
Yesterday Tony McNulty, a Home Office minister, said a national DNA database
was not a “silver bullet” and rejected calls for a mandatory one.
Even the police are unsure. Tony Lake, chief constable of Lincolnshire and
chairman of the Association of Chief Police Officers’ forensics panel, said:
“I don’t doubt we would solve more crime if everyone was on the DNA
database, but I don’t know exactly how much more.
“I don’t think people are ready for the ethical consequences of having a
universal DNA database. DNA is hugely important and we have masses of
success with it, but it is only one tool in the box.”
Concerns over the national database’s expansion will now be tested in court.
Next week two people charged with offences but never convicted will ask the
European Court of Human Rights to remove them from the database. If they
succeed, nearly 15% of records will have to be removed.
If the current rules are upheld, the database will continue growing rapidly.
Since 2001 about 490,000 subjects’ samples have been added each year; in
2005-6, more than 715,000 samples were added.
Mandatory or not, the question of how DNA is used and what safeguards are
necessary will not go away.
The pros and cons of using DNA evidence
The strengths
New techniques have improved the statistical certainties of DNA tests from
about one in 50m to one in a billion
DNA profiles can now be obtained from samples that are either very small or
many years old
The increasing number of people on the national DNA database means that
“familial DNA profiling” can be used to catch the perpetrators of unsolved
cases. James Lloyd, for example, was convicted of raping four women 20 years
after he committed the crimes. His sister’s DNA was taken after she was
stopped for a motoring offence and was found to be similar to DNA from samples of semen from his victims.
The weaknesses
The connection between the presence of DNA and guilt is not straightforward.
Person A’s skin cells can be transferred to Person B - by shaking hands, for
example - and then deposited at a site that Person A has never visited.
Experts also point out that some people shed skin cells more prolifically
than others
Many crime scene samples contain a mixture of different people’s DNA
Experts also warn that false DNA traces, such as cigarette butts taken from a
bar, could be planted at crime scenes to mislead police
